Tennis balls are tested in a machine to see how many bounces they can withstand before they fail to bounce 30% of their dropping height. Two brands of balls (Wand P) are compared. Tradition, the...

Tennis balls are tested in a machine to see how many bounces they can withstand before they fail to bounce 30% of their dropping height. Two brands of balls (Wand P) are compared. Tradition, the effect of shelf life on these brands is tested. Half of the balls of each brand are 6 months old, the other hall, fresh. Using a two-way analysis of variance, what conclusions can you reach? The data are shown here: